Cell phone usage does not increase the risk of developing the most common type of brain tumor, known as glioma, according to the results of a four-year study performed by the London-based Institute of Cancer Research and three British universities.

The survey was the largest ever published on the subject, and seems to suggest similar findings in other studies are indeed correct. Talk of a heightened cancer risk with cell phones was commonplace in medical circles earlier this decade, however evidence was no more than circumstantial.

The study also disproved Swedish scientists who said rural residents are at higher risk because mobile devices broadcast more intense signals there. The researchers said they found no evidence of that in their study.

If any health risk existed from mobile phones, the researchers argued, it would have been from the analog phones used years ago. But again, no evidence of a heightened risk was found there.

Altogether, 966 people with glioma brain tumors and 1,716 healthy respondents were surveyed on their mobile phone usage and what phones they had used.

Approximately 20,000 new US and 4,000 new UK cases of brain tumors are diagnosed each year, according to medical statistics.